(a) General rule.--Townships now in existence and those to be created are divided into two classes:
(1) townships of the first class; and
(2) townships of the second class.
(b) Township of the first class.--A township of the first class shall be a township having a population of at least 300 inhabitants to the square mile and:
(1) is functioning as a township of the first class as of June 24, 1931; or
(2) was created after June 24, 1931, as a township of the first class in the manner provided in this part.
(c) Township of the second class.--A township that is not a township of the first class or a home rule municipality shall be classified as a township of the second class.
(d) Change between classes.--A change from one class to the other shall be made only as provided by this part or the laws relating to townships of the second class.